1. Field of the Invention
The present invention relates to ink jet printhead cartridges, and, more particularly, to an ink jet printhead cartridge having an ink fill access port in fluid communication with the filter tower.
2. Description of the Related Art
An ink jet printhead cartridge combines ink storage and drop ejection functions into a unitary package. The ink jet printhead cartridge includes a body having a base for attachment of a printhead. The ink reservoir may include one or more chambers containing an ink-saturated porous material, such as for example, a polyurethane foam or felt. The printhead includes a nozzle plate having a plurality of ink jetting nozzles, which is attached to a substrate having fluidic passages and chambers for receiving and transporting ink to the ink jetting nozzles, and has selectable electrical components, e.g., heater or piezoelectric elements, which when actuated cause ink to be ejected from one or more of the ink jetting nozzles.
An interconnection between the ink reservoir and the printhead is provided, at least in part, by a tower, sometimes also referred to as a standpipe, which extends upwardly from the base. In order to prevent the introduction of particulate matter and/or air bubbles into the flow path of the interconnection from the ink reservoir to the ink jetting nozzles of the printhead, a filter is typically attached to the tower, and hence, the tower/filter combination is sometimes also referred to as a filter tower assembly. The filter may be in the form of a fine mesh stainless steel filter affixed to the entrance of the tower. The filter also acts as a capillary drain, allowing ink passage upon demand.
Typically, an ink jet printhead cartridge is filled with ink during manufacturing by inserting one or more needles into the porous foam material and injecting a set volume of ink into the porous foam material. Access is typically through the top of the reservoir prior to attaching the lid. Although commercially viable, this process has unnecessary variables that influence the page yield the customer ultimately realizes.